The present invention relates in general to apparatus for orienting products and, more specifically, to apparatus having at least two conveyor formations, separate drives for the conveyor formation, sensors for detecting the orientation of each product and controls for varying the speed of movement of the conveyor formations to annul a displacement of a principal axis of a product from a condition in which the principal axis is perpendicular to the direction of transportation. The present invention has been developed with particular attention to its possible use in the field of automatic packaging machines.
In this field of use, products being packaged (for example confectionery products such as bars of chocolate and the like, possibly already contained in individual wrappers) are currently advanced with one of their principal axes, usually the major axis, arranged approximately perpendicular to the direction of advance. This situation is common, for example, in machines which form so-called "multi-pack" packages, in which individual products inserted in respective "flow-pack" or "form-fillseal" wrappers are advanced towards a further wrapping station for insertion, in groups containing a predetermined number of units, in similar packages of larger dimensions.
As the products advance, phenomena of various kinds, either random in character or pseudo-deterministic in nature, such as slippage on the conveyor belt, slight holding back of the product resulting from a certain outward projection of the longitudinal join in the wrapper or the presence of a flap at one end of the wrapper which is slightly larger than the flap at the opposite end, may mean that an individual product does not advance with its principal axis exactly perpendicular to the direction of advance.
A situation of this kind may have adverse effects, for example when a flow of products advancing sideways must be transferred onto a bladed conveyor which provides for their positive entrainment. For instance, if the blades have a certain transverse length, or if the bladed conveyors engage each product by means of several entrainment nibs or teeth, an incorrectly arranged product can result in undesirable interference with the entrainment devices.
Moreover, account must also be taken of the fact that any disalignment from the desired position may be further aggravated during passage from one conveyor to another which is advancing at a faster speed.
Finally, it should be noted that, although it is possible to compensate to a certain extent for limited displacement from the position perpendicular to the direction of entrainment, (for example by the formation of an accumulation) displacement beyond a certain value may become irreversible (for example when the products are arranged at approximately 45.degree. to the direction of advance), with the consequent risk of the product being "chewed up" by the wrapping machine and consequent fouling if not damage to or blockage of the machine itself.
An object of the present invention is to provide apparatus which remedies the aforesaid problems completely and ensures that, at its output, the products are arranged with their principal axes in as perpendicular an orientation as possible to the direction of advance.
According to the present invention, this object is achieved by an apparatus which has at least two conveyor formations which act in the direction of transportation, separate drives for the conveyors which can impart different speeds of movement, sensors for detecting the orientation of each product and generating at least one signal indicative of the displacement of the principal axis of each product from the condition in which its is perpendicular to the transportation direction, and controls which are sensitive to the at least one signal of the sensors to act on the drives for varying the speed of movement of the conveyor formations to annul the displacement.
Essentially, the present invention utilize the known principle according to which, by providing a conveyor comprising two entrainment formations (for example endless conveyor belts) which can be advanced at different speeds, it is possible to vary the orientation of a product transported on the two entrainment formations. For example, it is known to use this principle to rotate products arranged "across" the direction of advance through 90.degree. to make them advance "lengthwise".
Another object of the present invention is to provide a method for orienting the products quickly and efficiently with the use of the apparatus of the type specified above.
This aspect of the present invention is based on the observation that, once the fact that a certain product is advancing with its principal axis not exactly perpendicular to the direction of entrainment has been detected, it is not necessary to wait until the degree of its displacement from the desired position has been detected before the necessary corrective action is initiated.
A further object of the present invention is to provide a method of regulating apparatus of the type specified above to operate preferably in accordance with the method of the present invention.